The paper first describes the previously proposed control strategy for a series-parallel hybrid electric vehicle (HEV) and an Extended Range Electric Vehicle (EREV), which combines a heuristic RB controller with an instantaneous optimisation strategy. The optimisation algorithm is based on the equivalent consumption minimisation strategy (ECMS), which optimises the engine operating point over proper 1D or 2D regions of the engine torque map at every sampling instant. In order to try to minimise the equivalent fuel consumption, the ECMS approach can command frequent changes of engine operating points, thus affecting NVH features of the HEV/EREV power train. The paper proposes and verifies an extended ECMS approach that penalizes for frequent changes of engine operating point, thus being able of reducing the NVH content and in fact improving the fuel economy when applied to a full (forward-looking) power train model.